The present invention relates to an electronic device, for example, a technology applicable to a semiconductor device having a power transistor and an electronic device having the semiconductor device.
A semiconductor device is sometimes mounted on a mounting board by exposing a die pad from a semiconductor package member of the semiconductor device and coupling the entire lower surface of the exposed die pad to a pad of the mounting board. A large adhesive force is secured by coupling the entire lower surface of the die pad to the pad of the mounting board. The area of the pad of the mounting board is therefore made a little greater than the area of the entire lower surface of the die pad. In particular, when the semiconductor device includes a semiconductor chip having a power MOSFET or the like that generates heat greatly upon use, the heat radiation property is secured by releasing the heat thus generated upon use through a joint between the entire bottom surface of the die pad and the pad of the mounting board greater than the semiconductor chip.
As a result of the related art search after completion of the present invention, Japanese Patent Laid-Open No. 2001-127228 (Patent Document 1) was found as a related art. An object of Patent Document 1 is to realize a power type resin molded semiconductor device while reducing the size of the semiconductor device and increasing the number of terminals. A means for satisfying the above-mentioned object is disclosed as follows (refer to FIGS. 7A and 7B of Patent Document 1). A resin film (3) has thereon a die pad (4) and a plurality of signal coupling leads (5) that surround the die pad. The die pad (4) has thereon a semiconductor chip (11) via an adhesive (12) and at the same time, the semiconductor chip (11) and each of the signal coupling leads (5) are coupled to each other with a fine metal wire (13). On the upper surface side of the resin film (3), the resin film (3), the die pad (4), the signal coupling leads (5), the semiconductor chip (11), the metal wire (13), and the like are molded with a resin package (14). The die pad (4) is equipped with a heat radiation portion (4a) protruding below the resin film (3), while each of the signal coupling leads (5) is equipped with a terminal land portion (6) protruding below the resin film (3). Since the die pad (4) is smaller than the semiconductor chip (11), the semiconductor chip (1) may be equipped with the terminal land portion (6) therebelow. The numbers in the parentheses are those described in Patent Document 1.